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Connexin Test (GJB2 Sequencing and DFNB1 (GJB6) Deletions)
Clinical Genetic Test
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offered by
Laboratory for Molecular Medicine
View lab's test page
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GTR Test Accession: Help GTR000509100.8
INHERITED DISEASECONNECTIVE TISSUEEAR, NOSE, THROAT ... View more
Last updated in GTR: 2023-12-05
View version history
Last annual review date for the lab: 2023-12-01 LinkOut
At a Glance
Test purpose: Help
Diagnosis
Conditions (6): Help
Hereditary hearing loss and deafness; Autosomal dominant keratitis-ichthyosis-hearing loss syndrome; Autosomal dominant nonsyndromic hearing loss 3A; ...
Genes (2): Help
GJB2 (13q12.11), GJB6 (13q12.11)
Methods (2): Help
Molecular Genetics - Deletion/duplication analysis: Droplet Digital PCR; ...
Target population: Help
Individuals with hearing loss
Clinical validity: Help
Not provided
Clinical utility: Help
Not provided
Ordering Information
Offered by: Help
Laboratory for Molecular Medicine
View lab's website
View lab's test page
Specimen Source: Help
Who can order: Help
  • Genetic Counselor
  • Health Care Provider
  • Licensed Physician
  • Nurse Practitioner
  • Physician Assistant
  • Registered Nurse
Test Order Code: Help
lmCX26-av3_L; lmCX30-bv2_L
View other test codes
Lab contact: Help
Clinical Testing Assistant, , Laboratory Contact
lmm@partners.org
617-768-8500
Contact Policy: Help
Laboratory can only accept contact from health care providers. Patients/families are encouraged to discuss genetic testing options with their health care provider.
How to Order: Help
Physician must complete test requisition and submit a blood sample (see sample requirements)
Order URL
Test service: Help
Clinical Testing/Confirmation of Mutations Identified Previously
Test development: Help
Test developed by laboratory (no manufacturer test name)
Informed consent required: Help
Yes
Test strategy: Help
Given the large contribution of the connexin 26 and connexin 30 genes to genetic causes of hearing loss, the testing of these two genes is often a the first line in a diagnostic work up. Genetic testing for these two genes would be recommended in a child born with hearing … View more
Pre-test genetic counseling required: Help
No
Post-test genetic counseling required: Help
No
Conditions Help
Total conditions: 6
Condition/Phenotype Identifier
Test Targets
Genes Help
Total genes: 2
Gene Associated Condition Germline or Somatic Allele (Lab-provided) Variant in NCBI
Methodology
Total methods: 2
Method Category Help
Test method Help
Instrument
Deletion/duplication analysis
Droplet Digital PCR
Sequence analysis of the entire coding region
Bi-directional Sanger Sequence Analysis
Applied Biosystems 3730 capillary sequencing instrument
Clinical Information
Test purpose: Help
Diagnosis
Target population: Help
Individuals with hearing loss
View citations (2)
  • Shearer AE, Hildebrand MS, Schaefer AM, Smith RJH. Genetic Hearing Loss Overview. 1999 Feb 14 [updated 2023 Sep 28]. In: Adam MP, Feldman J, Mirzaa GM, Pagon RA, Wallace SE, Bean LJH, Gripp KW, Amemiya A, editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2024. PMID: 20301607.
  • Molecular diagnosis of hearing loss. Brown KK, et al. Curr Protoc Hum Genet. 2012;Chapter 9:Unit 9.16. doi:10.1002/0471142905.hg0916s72. PMID: 22241658.
Variant Interpretation:
What is the protocol for interpreting a variation as a VUS? Help
All VUS's are reported

Are family members with defined clinical status recruited to assess significance of VUS without charge? Help
Yes. *Please call. Offered on a case-by-case basis.

Will the lab re-contact the ordering physician if variant interpretation changes? Help
No. Ordering provider is encouraged to periodically contact the lab to see if there is any new information available. However, if the ordering physician has GeneInsight Clinic, they may receive automatic updates on classification through that program.
Research:
Is research allowed on the sample after clinical testing is complete? Help
No
Recommended fields not provided:
Clinical validity, Clinical utility, Sample negative report, Sample positive report
Technical Information
Test Procedure: Help
1 - Sanger sequencing of exon 1 and exon 2 of the GJB2 (connexin 26 gene (NM_004004)) 2 - DFNB1 (GJB6) Deletions: Droplet digital PCR (ddPCR) is performed using a probe at GRCh38 chr13:21003868-21003954 to test for the presence or absence of the previously reported deletions in the DFNB1 (GJB6 … View more
Availability: Help
Tests performed
Entire test performed in-house
Analytical Validity: Help
This test is greater than 99.9% accurate in detecting variants in the sequence analyzed.
View citations (1)
Assay limitations: Help
This test does not detect large deletions in GJB2 or variants in non-coding regions that could affect gene expression. This test does not include sequencing of GJB6. Deletions that do not overlap with the following region will likely not be detected: GRCh37 chr13:21003868-21003954.
Proficiency testing (PT):
Is proficiency testing performed for this test? Help
Yes

Method used for proficiency testing: Help
Intra-Laboratory
VUS:
Software used to interpret novel variations Help
Alamut, UCSC Genome Browser, gnomAD, ExAC, ESP, 1000 Genomes, PolyPhen, SIFT, AlignGVGD, and more.

Laboratory's policy on reporting novel variations Help
All novel VUS's are reported
Recommended fields not provided:
Test Confirmation, Citations to support assay limitations, Description of internal test validation method, PT Provider, Description of PT method, Major CAP category, CAP category, CAP test list
Regulatory Approval
FDA Review: Help
Category: FDA exercises enforcement discretion
Additional Information

IMPORTANT NOTE: NIH does not independently verify information submitted to GTR; it relies on submitters to provide information that is accurate and not misleading. NIH makes no endorsements of tests or laboratories listed in GTR. GTR is not a substitute for medical advice. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.